In recent years, the technology of multimedia storage and interactive accessing has converged with that of network communications technologies, to present exciting prospects for users who seek access to remotely stored multimedia information. Particularly exciting has been the recent prominence of the Internet and its progeny, the World Wide Web. The Internet and the Web have captured the public imagination as the so-called "information superhighway." Accessing information through the Web has become known by the metaphorical term "surfing the Web."
The Internet is not a single network, nor does it have any single owner or controller. Rather, the Internet is an unruly network of networks, a confederation of many different networks, public and private, big and small, whose human operators have agreed to connect to one another.
The composite network represented by these networks relies on no single transmission medium. Bi-directional communication can occur via satellite links, fiber-optic trunk lines, phone lines, cable TV wires, and local radio links. However, no other communication medium is quite as ubiquitous or easy to access as the telephone network. The number of Web users has exploded, largely due to the convenience of accessing the Internet by coupling home computers, through modems, to the telephone network. As a consequence, many aspects of the Internet and the Web, such as network communication architectures and protocols, have evolved based around the premise that the communication medium may be one of limited bandwidth, such as the telephone network.
To this point the Web has been used in industry predominately as a means of communication, advertisement, and placement of orders. The Web facilitates user access to information resources by letting the user jump from one Web page, or from one server, to another, simply by selecting a highlighted word, picture or icon (a program object representation) about which the user wants more information. The programming construct which makes this maneuver possible is known as a "hyperlink".
In order to explore the Web today, the user loads a special navigation program, called a "Web browser" onto his computer. A browser is a program which is particularly tailored for facilitating user requests for Web pages by implementing hyperlinks in a graphical environment. If a word or phrase, appearing on a Web page, is configured as an hyperlink to another Web page, the word or phrase is typically given in a color which contrasts with the surrounding text or background, underlined, or otherwise highlighted. Accordingly, the word or phrase defines a region, on the graphical representation of the Web page, inside of which a mouse click will activate the hyperlink, request a download of the linked-to page, and display the page when it is downloaded.
There are a number of browsers presently in existence and in use. Common examples are the NetScape, Mosaic and IBM's Web Explorer browsers. Browsers allow a user of a client to access servers located throughout the world for information which is stored therein. The information is then provided to the client by the server by sending files or data packets to the requesting client from the server's storage resources.
Part of the functionality of a browser is to provide image or video data. Web still image or video information can be provided, through a suitably designed Web page or interface, to a user on a client machine. Still images can also be used as Hypertext-type links, selectable by the user, for invoking other functions. For instance, a user may run a video clip by selecting a still image.
A user of a Web browser who is researching a particular area of interest will often move from one home page, to another, to another, etc., by hyperlinking from each successive page to the next. As discussed above, each successive Web page must be downloaded. Web surfers have become acutely aware of the often significant amounts of real time required to download a Web page, video clip, etc. This time delay can often be measured in tens of seconds, or even in minutes. While such a download is taking place, the user must sit idle and wait.
Thus, an important design objective in an Internet/Web architecture is throughput. Unfortunately, the bandwidth of most Internet communication media is limited, and the volume of traffic is growing as more users gain access to the Internet. Therefore, users are becoming acutely aware of the delays inherent in downloading information.
It is foreseeable that the future will hold a race between the increasing throughput capacity of state-of-the-art communication media, such as fiber optic communication lines, versus the ever-increasing volume of traffic as more and more users take advantage of more and more information coming on line.
For the present, users, clicking on a hyperlink, have no way of knowing, in advance, how much information lies behind the hyperlink, how long the information will take to download, or how much information is displayed prior to the end of the download process. (With regard to the latter issue, some Web pages cannot be viewed at all during the download process. Others provide usable slider bars, so that a user can view the portion already downloaded, while the remainder is still in transit Others use a rastering scheme to allow an image to be viewed while interspersing raster lines are still in transit.)
Therefore, conventional Web browsers have had the drawback that users have been unable to tell how long a download for a given hyperlink would take, unless they actually clicked on the hyperlink. After that, they were committed to waiting out the download, regardless of how long it took, unless they took the action of terminating the download.